Sample detector

Abstract

A sample detector is comprised of a first group of optical fibers having exit end surfaces arranged in the direction perpendicular to the shifting direction of the carrier, a second group of optical fibers having entrance end surfaces arranged opposite said exit end surfaces of the first group of optical fibers, a plural number of light emitting diodes arranged in the vicinity of the entrance end surfaces of the first group of optical fibers, a single photo detector element arranged in the vicinity of the exit end surfaces of the second group of optical fibers and a preamplifier connected to the output side of said photo detector element. Said sample detector is adapted in such a manner that the light emitting diodes are caused to glow consecutively, the light, having passed through the first group of optical fibers the carrier and the second group of optical fibers, is received by said photo-detector element, subjected to photoelectric conversion and amplified by said preamplifier. The presence of samples on the carrier is detected based on the outputs thus obtained.

We claim: 
     
       1. A sample detector for monitoring a moving carrier, comprising: a first optical fiber group including a plural number of optical fibers arranged in a direction perpendicular to the moving direction of said carrier and having exit end surfaces adjacent to said carrier,   a second optical fiber group including a plural number of optical fibers having entrance end surfaces arranged opposite to the exit end surfaces of said first optical fiber group and bundled exit end surfaces,   a plural number of light emitting elements arranged in the vicinity of the entrance end surfaces of the individual optical fibers of said first optical fiber group,   a photodetector element arranged in the vicinity of the bundled exit end surfaces of said second optical fiber group,   a preamplifier connected to the output side of said photodetector element,   said sample detector being so adapted as to detect the presence of samples applied onto said carrier based on outputs from said preamplifier, and   photometric means arranged adjacent to said first and second optical fiber groups and being operative when a time determined by the spacing between said first and second optical fiber groups and said photometric means has passed after the position of a sample on said carrier has been detected.   
     
     
       2. A sample detector for monitoring a moving carrier, comprising: a first optical fiber group including a plural number of optical fibers arranged in a direction perpendicular to the moving direction of said carrier and having exit end surfaces;   a second optical fiber group including a plural number of optical fibers having entrance end surfaces arranged opposite to the exit end surfaces of said first optical fiber group;   a plural number of light emitting elements arranged in the vicinity of the entrance end surfaces of the individual optical fibers of said first optical fiber group;   a photodetector element arranged in the vicinity of the exit end surfaces of said second optical fiber group;   a preamplifier connected to the output side of said photodetector element; and   means for detecting an edge of a sample by detecting a turning point from a time at which said outputs from the preamplifier corresponding to all the light emitting elements are higher than a preset level to another time at which said outputs from the preamplifier corresponding to at least one of the light emitting elements is lower than said preset level, and for detecting the other edge of the sample by detecting a time at which said outputs from the preamplifier corresponding to all the light emitting elements are higher than said preset level once again.   
     
     
       3. A sample detector according to claim 2 further including means for energizing individual light emitting elements, and wherein the means for producing output signals representative of a preset level includes means for measuring the outputs from the preamplifier for each light emitting element and means for storing said measured outputs.